1. Field of the Invention
The present invention relates to a display apparatus which displays an image using a liquid crystal panel. Particularly, the present invention relates to an optical sheet holding structure and a display apparatus which has the optical sheet holding structure capable of preventing an occurrence of problems such as uneven luminance, or luminance degradation and the like, due to wrinkles, bending, or the like of the optical sheet used in the display apparatus, while achieving slimmed border of the display apparatus.
2. Description of Related Art
A display apparatus using a liquid crystal panel is provided with an optical sheet for diffusing or collecting light emitted from a light source. The optical sheet is provided between the liquid crystal panel and the light source. In this case, it is necessary for the optical sheet to be held by a positioning member so as to be parallel to the liquid crystal panel.
The optical sheet includes one or a plurality of optical films. The optical sheet is thermally expanded due to heat principally from the light source. Thereby, the optical sheet is positioned and held with a margin given by as much as the expansion, in such a way that only a part thereof is fixed to the positioning member. For example, the optical sheet is a rectangular shape, and is provided with a plurality of holes in an edge part on one long side thereof. When penetrating the plurality of holes by positioning pins provided on the positioning member, the optical sheet is hooked thereto. In this case, since an edge part of the optical sheet on a side opposite to the one long side is not fixed, wrinkling or bending does not occur in the optical sheet when thermally expanded.
Further, in the display apparatus, increasing of size and thinning, and slimmed border are required. The holes for positioning of the optical sheet and the positioning member should be provided within a limited range of being hidden by the frame. In addition, various researches are executed on the holding structure of the optical sheet.